If the screenshots I'm looking at are anything to go on, there may be some loss of quality in the new release, but compared to what the original DVD looked like it's still an improvement.
Now take this with a grain of salt since I cannot get the frames to merge correctly. Why? Well it seems besides different aspect ratios, the frame appears ROTATED! The Platinum disc is rotated slightly counterclockwise in the frame below. I have no idea why. BUT as a result the merge isn't perfect, but you should get the idea.
Standard Edition:
Platinum:
Standard Luma, Platinum Chroma:
There is just less detail in the original release. Period.
I am floored that the Platinum has brighter whites in many places, but the eyes are whiter on the Standard. Strange.
Anyway, I think just the audio and the knees are all that's really needed to be fixed...